1

The world's only hellish because of the local industry

2

The natives can't readily survive offworld any more

3

The natives think they're morally obliged to stay

4

Its sponsor uses it as a prison or dumping ground

5

The sponsor lies about the real nature of the world

6

The hellish trait of the world is going to get much worse

7

The hellish conditions spawn some precious substance

8

The locals live under prison-like police-state conditions